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INA128: INA128

user4973896
Expert 1555 points

Part Number: INA128
Other Parts Discussed in Thread: INA149, INA148,

hello，now I I met a problem。I want to record several signals，for example V1p_in+  ,V1p_in- ,V2p_in+  ,V2p_in- .   the four signal has Different amplitude。The range of V1p_in+ signal  is from -65V to +60V,while The range of V1p_in- signal  is from -450V to +250V   ,The range of V2p_in+ signal  is from -300V to +50V,The range of V2p_in- signal  is from -3000V to +500V,  If I want to achieve an acquisition accuracy of 1%, is it necessary for each signal to be separate?First through the voltage divider, then conditioning, and finally enter the ADC mode。

  • 0
    TI__Guru 74331 points

    First, you would need to bring the input voltages within the input voltage range of the instrumentation amplifier you plan on using; in case of INA128, within Vcm of 2V from either rail.  Thus, using +/-15V supplies would require a voltage divider of at least 230 to bring 3kV input voltage within 13V input voltage range of INA128.  Therefore, in order to achieve accuracy of 1%, you would have to use resistors with matching better than 1%.  Please take a look at INA148 and INA149, which can accomodate voltages with input common-mode up to 550V.

  • 0 in reply to Marek Lis
    TI__Genius 11135 points
    Zhang

    We haven't heard back from you so we assume this answered your question. If you need more help just post another reply below.

    Thanks
    Dennis